Best Buy offers the Western Digital Caviar Green 2TB Serial ATA 3Gb/s 4″ Internal Hard Drive, model no. WDBAAY0020HNC-NRSN, for $79.99 with free shipping. That’s $0.04/GB and the lowest total price we could find now by $7. Sales tax is added where applicable. This drive purports to consume up to 40% less energy than standard mechanical drives. It features a 32MB cache.